There is a practical technology to detect a face of a photographed person in a digital image taken with a digital camera. This technology is utilized for other image processes, such as changing the brightness of an image to show the face with optimum brightness, and trimming the periphery of the face (hereinafter, face area) to display it in full screen.
The information (position, etc) of the detected face area can be stored, together with the shooting date and such, as accompanying information associated with the digital image. Accordingly, by equipping an image processing device or an image viewer with such a face area detecting function, it is possible to provide high added-value services using the information of the face area. Here, the image viewer is an image processing software for displaying (the list or the selection of the images) and editing (copy, delete, trim, rotate and resize) the images, and sometimes has a function to produce a layout image which contains plural selected images inserted into image display frames.
For example, Japanese patent laid-open publication No. 2004-178163 discloses an image processing device which detects the face area of a photographed person in image data and combines a preset decorative image, such as a hat or an eyeglass, of appropriate size and position with the person.
Also, Japanese patent laid-open publication No. 2004-207987 discloses a print system including a digital camera that detects a face area from the image data, and a memory to store the position and size information of the face area. Based on this information, the photographed person is printed, on the printer, with an appropriate position and size.
Further, Japanese patent laid-open publication No. 2002-042116 discloses an image processing device which retrieves image data of several persons, and adjusts these data such that every face has approximately the same size.
The image data thus adjusted is suitable for making a portrait list or such a layout image to list portraits. However, if a group photograph containing several persons is used in a typical layout image whose image display frames usually have the same size, each person may sometimes be too small to see. In this case, the user takes trouble to adjust each of the images and insert them into the image display frames.